The invention relates to a motor vehicle and method for operating a motor vehicle having a driver assistance device which is designed to independently guide the motor vehicle during travel of the motor vehicle and in this case can be changed over between at least two assistance modes which differ from one another in terms of a degree of independence of the driver assistance device when guiding the motor vehicle.
The term “guiding the motor vehicle” comprises here, on the one hand, the steering of the motor vehicle (following the course of a road, orienting the motor vehicle within a lane, lane-changing maneuver), which is also referred to as lateral guidance, and, on the other hand, the control of the speed of the motor vehicle (accelerating, braking, emergency braking, maintaining the speed), which is also referred to as longitudinal guidance.
A driver assistance system of the specified type is known from DE 10 2010 022 433 A1. According to said document, a driver assistance system can, in a fully automatic assistance mode, guide the vehicle completely independently. The driver of the motor vehicle then has to operate neither the steering wheel nor the pedals of the motor vehicle during travel and can therefore turn his attention to other things, for example the operation of an infotainment system, for a relatively long period.
However, independent guidance of the motor vehicle can also be understood as meaning a semi-automatic assistance mode in which the degree of independence of the driver assistance system is reduced when guiding the motor vehicle and which can then include, for example, merely of the functionality of adjusting the speed of the motor vehicle to a desired or set speed which is predefined by the driver by setting a value of the corresponding driving parameter of the driver assistance system (cruise control).
A further desirable assistance mode is the autonomous guidance of the motor vehicle by a driver assistance device. In contrast to the fully automatic assistance mode, in the autonomous assistance mode the driver assistance device also decides which values are to be implemented for the driving parameters (desired distances, desired speed) for a currently implemented driving maneuver and/or which driving maneuvers (lane change, turning off the road, parking and the like) are to be implemented. In contrast, in the fully automatic assistance mode, provision is made for the driver to use a user interface to predefine which driving maneuvers are to be implemented or which distances and speeds are to be adjusted by the driver assistance device during a currently implemented driving maneuver when traveling along a lane. Another difference between the two assistance modes can relate to how the driver assistance device reacts in the event of an unforeseen development of events on the road, that is to say if safe guidance is no longer ensured by the driver assistance device. In the fully automatic assistance mode, provision is then made for the driver assistance device to be deactivated and to transfer control of the motor vehicle to the driver, while, in contrast, in the autonomous assistance mode, the driver assistance device itself places the motor vehicle in a safe state, for example by stopping the motor vehicle.
Depending on the currently active assistance mode, certain guidance tasks are carried out independently by the motor vehicle, i.e. without involvement of the driver, during travel. However, in this case, it must be ensured, for each assistance mode in which the driver assistance device can be operated, that the driver is always clear as to the degree to which the driver assistance system monitors and guides the motor vehicle, which intervention possibilities are still available to the driver himself during the guidance of the motor vehicle and which guidance tasks the driver must necessarily carry out himself. If the driver loses an overview here, his safety may be compromised. If the driver wrongly believes, for example, that the driver assistance device is in the fully automatic assistance mode and therefore lets go of the steering wheel in order to deal with the infotainment system, the vehicle may run off the road in this case because the driver assistance device is, for example, not activated at all, that is to say a fully manual driving mode is demanded of the driver (this is therefore referred to as the manual assistance mode here).
The range of independence of the driver assistance device (automation range) which extends from manual driving to partial and full automation and then on to autonomy should in its complexity in future be transparent and comprehensible to the user in terms of operating it. Important properties of future operating concepts are a manageable complexity of these four specified assistance modes, clear delimitability between the individual assistance modes and characteristic operating modalities within the individual assistance modes. Whereas established operating elements such as buttons, a steering wheel or a lever are available for partial automation (for example cruise control, active lane control, i.e. lane-keeping assistance), until now there have only been conceptual approaches to the prototypical operation of full automation and autonomy. These approaches are frequently merely supplements or extensions of existing operating concepts and constitute isolated solutions. Such isolated solutions generally do not amount to anything more than mere functional integration into existing operating elements, which leads to an increase in the functional density of the individual operating elements and therefore is not targeted owing to the variety and complexity of the operating devices which result therefrom. The manageability and functional variety of current operating elements have already been fully exploited.